Hello and welcome to the Shibboleth documentation. In here we will document as much as possible about Shibboleth authentication.
The documentation here is written for Shibboleth IdP version 4!
What is Shibboleth?
Shibboleth is an Identity Manager (also called Identity Provider or IdP) that providers Single Sign-On services. This means that you only have to enter your username and password once and all other connected services (called Service Providers or SP) no longer require you to login. You have obviously noticed that when accessing Toledo and afterwards Intranet. All the data that the IdP has can be transmitted to the SP, thus it no longer has to contain a database for user info.
How does it work?
It depends on what authentication system you use. You can use SAML2, CAS and OpenID Connect.